The invention consists of a machine for automatically assembling cardboard boxes, boxes essentially of those comprised of three pieces, two of which are applied laterally forming the front ends thereof on a main piece provided with laps that fold and fasten to said front ends.
The new machine considerably improves the assembling of this type of container that, on the other hand, proves to be relatively complex inasmuch as it is necessary to combine different cardboard parts in order to form the box assembly.
There are different machines that fold cardboard boxes by means of an automatic continuous process.
Among these machines, one can point out those that automatically carry out the assembly of the type of boxes that include a main piece or sheet and two independent lateral sheets comprising the front ends that are attached to the main sheet or piece during the assembly process. These independent sheets are attached to some laps that form part of the main sheet or piece.
The current machines that assemble this type of box include different devices, that in general are very complex, mainly the devices which position the independent lateral sheets in the corresponding place of the box during assembly thereof.
This all has a negative effect on the assembly process, slowing same down, at the same time that sometimes the product obtained is not as good as expected.
In order to achieve the aims and in order to avoid the inconveniences mentioned in the preceding sections, the invention proposes a machine for assembling cardboard boxes.
The cardboard boxes are preferably of the type that is comprised of three sheet-like pieces, two of which comprise the front ends and a third main piece, where the front ends are fastened by means of an adhesive. Hence, the main sheet or piece comprises the bottom, the sides and some laps on which the other sheets or two pieces forming the front ends are attached with the help of adhesive, as mentioned above.
In principle the machine has a forming station wherein a mandrel or top male forming element descends vertically on a folding mold, where the main sheet or piece comprising the bottom, sides and small laps has been previously placed.
Besides, the machine includes a bottom folding mold opposite the mandrel or top male forming element, at the same time that it is arranged under the cited mandrel. It also includes a feeder of sheets or main pieces that move by some guides established on a horizontal plane located between the male forming element and the bottom mold.
First of all the machine is characterized in that the forming station has two side feeders located in a transversal arrangement with respect to the forward movement of the sheet or main piece. These feeders are the receivers of the lateral sheets forming the front ends of the boxes, in such a way that these lateral sheets are stacked vertically with a slight slant.
Another characteristic is the inclusion of the conveying means of such lateral sheets or front ends independent to the forming station, in a synchronized manner. Such means essentially consist of some devices whose purpose is to collect the independent sheets of the front ends from the side feeders in order to convey them to the forming station placing them precisely in the sides of the main sheet. In a subsequent step, the independent lateral sheets are inserted and therefore applied to the box when the mandrel or top male forming element moves vertically downward in order to carry out the assembly of the box, in such a way that in this descending operation of the mandrel and assembling of the box, said mandrel conveys the main sheet as well as the two independent lateral sheets in its vertical movement downward, the front ends or independent lateral sheets attaching to some laps integral with the bottom and sides of the main pieces by means of adhesive glue.
Each one of the lateral sheets or independent front ends conveying device comprises the following structure:
Two tiltable arms that joint at one of their ends in respective shafts arranged in the same direction through a motor element.
A cross shaft coupled freely in the free ends of the tiltable arms.
At least one lever coupled jointedly by an end section in a shaft, a lever that acts as a guide and angular positioning to the cross shaft, because the cross shaft has a short extension fit in a guide rail of the lever.
A suction pad support integral to the cross shaft, suction pads that are responsible for securing the lateral sheets by suction during the conveyance thereof.
All of this is in order to convey one by one by means of angular rotation of approximately 180xc2x0 each lateral sheet of the front ends from the feeder to the forming station so that when the top male forming element descends, this male element simultaneously conveys the two lateral sheets of the front ends and the main sheet towards the matrix of the mold for folding the box.
Another characteristic of the machine is that the forming station includes some squares arranged vertically in correspondence with the vertical corners of the box to be formed, squares that are located in the arrival areas of the sheets or pieces of the front ends, at the same time that the squares have the task of prefolding some small side laps that are formed in the ends of said sheets of the front ends.
The squares essentially have a decreasing structure from top to bottom that favors the progressive forming of the side laps when the top male forming element acts when descending towards the matrix of the mold.
The machine also includes as a novel characteristic some pressure rotating rollers located in the sides of the top male forming element in correspondence with the mouth of the bottom folding mold. This is all so that when the top male forming element descends in order to form the box, the laps of the main sheet that originate in the bottom of the box collapse and are pushed against the lateral sheets of the front ends to favor their gluing.
The machine is also characterized in that the bottom folding or forming mold or matrix includes in its four corners some pairs of rotating rollers, some top ones with a cone-shaped structure and other bottom ones with a cylindrical structure. When the top male forming element descends for the forming of the box, the laps of the main sheets that originate in the ends of the sides collapse and are pushed towards the lateral sheets of the front ends in order to favor their gluing, the cone-shaped rollers facilitating the progressive folding of said laps of the sides of the box.
Finally, it should be pointed out that the folding mold includes as a novel characteristic some fingers with elastic retention, essentially by means of a spring, fingers that have the purpose of keeping some closing laps that originate in the free edges of the sides when the box has already been formed, folded. In this way, when the next box to be formed descends it does not fit inside the box already formed and in this way the latter is caused to descend.
Hereinafter to provide a better understanding of this specification and forming an integral part thereof, some figures in which the object of the invention has been represented in an illustrative and non-restrictive manner are attached hereto.